CA1312928C - High-gain ic amplifier - Google Patents
High-gain ic amplifierInfo
- Publication number
- CA1312928C CA1312928C CA000594865A CA594865A CA1312928C CA 1312928 C CA1312928 C CA 1312928C CA 000594865 A CA000594865 A CA 000594865A CA 594865 A CA594865 A CA 594865A CA 1312928 C CA1312928 C CA 1312928C
- Authority
- CA
- Canada
- Prior art keywords
- transistor
- amplifier
- voltage
- current
- transistors
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 101150034459 Parpbp gene Proteins 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 5
- XDXHAEQXIBQUEZ-UHFFFAOYSA-N Ropinirole hydrochloride Chemical compound Cl.CCCN(CCC)CCC1=CC=CC2=C1CC(=O)N2 XDXHAEQXIBQUEZ-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000003503 early effect Effects 0.000 description 1
- QHGVXILFMXYDRS-UHFFFAOYSA-N pyraclofos Chemical compound C1=C(OP(=O)(OCC)SCCC)C=NN1C1=CC=C(Cl)C=C1 QHGVXILFMXYDRS-UHFFFAOYSA-N 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/34—Negative-feedback-circuit arrangements with or without positive feedback
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/34—DC amplifiers in which all stages are DC-coupled
- H03F3/343—DC amplifiers in which all stages are DC-coupled with semiconductor devices only
- H03F3/3432—DC amplifiers in which all stages are DC-coupled with semiconductor devices only with bipolar transistors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45479—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An amplifier of the type having a differential input stage driving an active load which produces a single-ended output directed to a voltage-gain stage. The gain of the amplifier is isolated from the effects of load changes by a biasing circuit which forces the differential input stage to remain balanced at all times.
An amplifier of the type having a differential input stage driving an active load which produces a single-ended output directed to a voltage-gain stage. The gain of the amplifier is isolated from the effects of load changes by a biasing circuit which forces the differential input stage to remain balanced at all times.
Description
~ ~3~ 8 HIGH--G~:IN IC AMPLIFIER
BACRGROUND OF THE INV~NTION
1. ` Field of the Invention This invention relates to amplifiers. More par-ticularly, this invention concerns an amplifier of simple design which is formed as part of an integrated-circuit lIC) chip and provides high loop gain as well as other desirable characteristics.
BACRGROUND OF THE INV~NTION
1. ` Field of the Invention This invention relates to amplifiers. More par-ticularly, this invention concerns an amplifier of simple design which is formed as part of an integrated-circuit lIC) chip and provides high loop gain as well as other desirable characteristics.
2. Des ription of the Prior Art A wide variety of circuit designs have been used for amplifiers formed on IC chips. Operational amplifiers are employed extensively, and usually comprise a differen-tial input stage and a sinqle-ended output stage. Commonly, an active load such as a PNP current mirror will be coupled to the collectors of the dLf ferential-stage transistors .
The single-ended output of~the current mirror can drive one or more voltage-gain stagea. ~
~ Although such amplifiers have served many prac-tical purposes, their performance is not fully satisfactory in certain respects. For example, the gain of prior ampli-iers tends to vary to an undesired degree with changes in load, e.g. due to variations in ambient temperature. Still other aspects of prior amplifier designs requi~re lmprove-ment to meet the needs of modern pxecision linear components.
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SUMMARY OF THE INVENTION
In a preferred embodiment of the invention, to be described hereinbelow in detail, there is provided an ampli-fier of the type having a differential input stage driving an active load which produces a single-ended output direc~d to a voltage-gain stage. The gain of the amplifier is isolated from the effects of load changes by a biasing circuit which forces the differential input stage to remain balanced at all times. The overall gain of the amplifier can be extrem~ly high, for example, a gain of 2 million can be achieved in practice.
Other objects, aspects and advantages of the inven-tion will in part be pointed out in, and in part apparent from, the following detailed description considered together with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIGURE 1 is a schematic diagram showing the cir-cuit arrangement of a preferred amplifier in accordance with the invention.
DESCRIPTIO~ OF THE PREFERRED EMBODIMENT
Referring now to the lower-left-hand corner of ~he drawing, the amplifier includes an input circuit ter-minal 10 to whi~h the input signal is applied. The input signal may be derived from any of a variety of voltage sources, such as the output voltage of a band gap volt-age reerence. The input signal is directed from ter-minal 10 to the base of one transistor 12 of a simple matched differential pair with common emitters, i.e.
the emitters of the two transistors are coupled together, either directly (as shown) or indirectly. The base of the other differential transistor 14 receives a signal which, in this embodiment, is developed by a resistive negati~e ieed'cack circol- cou~led to the amplifier :
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The single-ended output of~the current mirror can drive one or more voltage-gain stagea. ~
~ Although such amplifiers have served many prac-tical purposes, their performance is not fully satisfactory in certain respects. For example, the gain of prior ampli-iers tends to vary to an undesired degree with changes in load, e.g. due to variations in ambient temperature. Still other aspects of prior amplifier designs requi~re lmprove-ment to meet the needs of modern pxecision linear components.
:
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SUMMARY OF THE INVENTION
In a preferred embodiment of the invention, to be described hereinbelow in detail, there is provided an ampli-fier of the type having a differential input stage driving an active load which produces a single-ended output direc~d to a voltage-gain stage. The gain of the amplifier is isolated from the effects of load changes by a biasing circuit which forces the differential input stage to remain balanced at all times. The overall gain of the amplifier can be extrem~ly high, for example, a gain of 2 million can be achieved in practice.
Other objects, aspects and advantages of the inven-tion will in part be pointed out in, and in part apparent from, the following detailed description considered together with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIGURE 1 is a schematic diagram showing the cir-cuit arrangement of a preferred amplifier in accordance with the invention.
DESCRIPTIO~ OF THE PREFERRED EMBODIMENT
Referring now to the lower-left-hand corner of ~he drawing, the amplifier includes an input circuit ter-minal 10 to whi~h the input signal is applied. The input signal may be derived from any of a variety of voltage sources, such as the output voltage of a band gap volt-age reerence. The input signal is directed from ter-minal 10 to the base of one transistor 12 of a simple matched differential pair with common emitters, i.e.
the emitters of the two transistors are coupled together, either directly (as shown) or indirectly. The base of the other differential transistor 14 receives a signal which, in this embodiment, is developed by a resistive negati~e ieed'cack circol- cou~led to the amplifier :
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output circuit, as will be described subsequently. Thus it will be seen that the amplifier in this embodiment is arranged as a follower with gain.
The collectors of the differential transistors 12 and 14 are connected respectively to split collectors 16, 18 of a PNP transistor 20 serving as a differential-to-single-ended converter. This transistor is arranged as a current mirror providing an active load for the diffexen-tial input stage. The upper collector 18 ~rovides a single-ended output from the current mirror, and drives the base of a PNP voltage-gain transistor 22, connected common emitter with transistor 20. The voltage-gain transistor 22 forms part of the output circuit.
The common emitters of transistors 20 and 22 to-gether provide an output terminal èlement for the first stage (the output terminal being identifiad on the drawing as circuit point 24). This output terminal in turn is con-nected to a further part of the output circuit generally indicated at 26. The output load comprises all the cir-cuitry connected to terminal point 24, including the output circuitry 26 and a multi-collector transistor 28 to be described hereinbelow.
The output circuitry 26 comprises a pair of Darlington-connected transistors 30,;32 which dri~e an external load 34. The load resistor 34 is paralleled by a resistor string 36 from which is derived a negative feed-back signal for the base of the second transistor 14 of the differential input pair.
The voltage-gain transistor 22 includes dual collectors which are connected toge~ther and to the emitter of another PNP transistor 38~acting~as a cascode. This cascode trànsistor 38;raises the output impedance of the amplifier, an important feature when the dynamic impedance of thè load is relatively high.
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The collector current of the cascode transistor 38 drives one transistor 40 of a current mirror generally indicated at 42. The other mirror transistor 44 supplies the bias tail current for the differential input transis-tors 12, 14. This mirror 42 thus reflects the current of the voltage-gain transistor 22 through the cascoded tran-sistor 38 to the emitters of the differential input tran-sistors 12, 14.
The emitter current for the ~ransistors 12, 14 will also flow in the load, that is,in the circuitry con-nected to circuit point 24. ~he load current comprises the current of the three paralleled collectors of transistor 28 and the very small amount of base current for the first Darlington transistor 30.
The current through the current mirror transistor 20 will be essentially equal to that of the~voltage-gain transistor 22. This is so because the currents in mirror transistors 44 and 40 will~necessarily be equall and there-fore the corresponding currents flowing in transistors 20 and 22 also must be equal. Thus the total signal current in the load at current point 24 will be essentially twice the current in the voltage-gain transistor 22. In effect, the transconductance of transistor 22 is doubled by this re-use of its current. This raises the overall gain by about ~ dB.
Yet a still more important result i5 however achieved by this biasing circuitry for the differential input stage transistors 12, 14. In more detail now, as noted above, the current mirror:42 forces the load current at circuit point 24 to split equally between the two common-emitter transistors ~0, 22. Moreovex, the base currents of transistors 20 and 22 also~will~be~equal, and will add re-spectively to the~equal currents of:the split collectors : ~ :: ; :
., .
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of transistor 20. (The cascode action of transistor 38 insures that the collector voltage of the voltage-gain transistox 22 will be very nearly the same as its base voltage -- and the base voltage of transistor 20 -- so that the Early effect will not unbalance the base currents Accordingly, the currents in the collectors of transistors 12 and 14 will be maintained essentially equal.
Consequently, it will be seen that the differ-ential input stage comprising transistors 12 and 14 always will be forced to ~e in balance by the biasing circuitry described. Changes in load current change ~he base volt-ages and the base currents of bo~h transistors 20 and 22 in such a way that the input stage remains in balance.
This in effect makes the amplifier gain independent of changes in the load.
It may be noted that the load at circuit point 24 is driven by the emitters of transistors 20 and 22.
This load connection to the emitters makes it possible to get at the collector current of the voltage-gain transistor 22 to use it to hold constant the ratio of the currents in the input stage transistors 12 and 14. This result is achiaved by holding constant the ratio of the Ioad current to the tail current of the input differential stage. As a consequence the differential voltage at the input stage is always extremely small.
The apparent load independence for the amplifier gain only works well over the range of currents where the transistors involved can operate normally. The Darlington transistors 30, 32 assist in that regard, making it possi-ble to develop substantial current for the external load 34 without reflecting significantly on the functioning of the previous stages. The Darlingtons also provide base bias for the cascode transistor 38.
The operating current for the ampiifier comes from the multi-collector transistor 28. This transistor is biased by a conventional circuit generally indicated at S0 which in the particular embodiment caused transistor 28 to produce a total of about 4~A, and reduced the powex supply voltage sensitivity. The transistor current is split by the multiple collectors, with about 3~A flowing into the common-emitter transistors 20, 22 and about l~A
driving another transistor 52. This latter transistor provides a tiny curre~t from its base to start the loop which runs from the emitter of the cascode transistor 38, to the current mirror 42, through the rigbt~hand input transistor 14 to the base of the voltage-gain transistor 22 and finally back to the cascode transistor 38. The little current from the base of transistor 52 insures that this loop will start. Its magnitude is comparable to the base current of the cascode transistor 38 so that it re-duces the error which results from the loss of collector current from voltage-gain transistor 22 by way of the base of the cascode transistor~.
A current-limiting arrangement also is included as part of the amplifier. A resistor 54 is connected in series with the output Darling~on transistor 32, which carries most of the output current, thereby to develop a voltage coxresponding to that output current. This voltage drives the base of a control transistor 56 which can rob emitter current from the`multi-collector transistor 28.
In order to make a big change in~the~emitter current, the control transistor 56 has to deliver a fairly large current to a resistor 58 in series with that emitter. This has the use~ul effect o "sharpening" the current limit, because when the control transistor ~ sufficient current for that purpose~ it has~a high transconductance,; so that fur-ther changes in the voltage~across~resistor 54 translate :
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directly to the emitter of transistor 28. Although the control transistor 56 has a high transconductance, transis-tor 28 has a low transconductance which goes even lower with the onset of current limiting. As the latter transis-tor current is reduced, the amplifier continues to operate more or less normally due to low sensîtivity to its load current, Ultimately, as the current from the collectors of transistor 28 is reduced to the base current required by transistor 30 to supply the load, the amplifier will be completely starved and the output voltage will fall with any furt~er loading.
Although a specific preferred embodiment of the invention has been described herein in detail, this has been for the purpose of illustrating the principles of the invention, and should not necessarily be construed as limitïng the invention since it is apparent that those skilled in the art can make many modified axrangements of the invention without departing from the true scope thereof.
For e~ample, the input matched differential pair could be replaced by a mismatched pair to force a proportional-to-absolute-temperature (PTAT) current for a band-gap circuit.
Alternatively, the regulated output could be used to light up a basic band-gap reference which could be boosted by the amplifier. Still other variations will be apparent to those of skill in the art.
*
output circuit, as will be described subsequently. Thus it will be seen that the amplifier in this embodiment is arranged as a follower with gain.
The collectors of the differential transistors 12 and 14 are connected respectively to split collectors 16, 18 of a PNP transistor 20 serving as a differential-to-single-ended converter. This transistor is arranged as a current mirror providing an active load for the diffexen-tial input stage. The upper collector 18 ~rovides a single-ended output from the current mirror, and drives the base of a PNP voltage-gain transistor 22, connected common emitter with transistor 20. The voltage-gain transistor 22 forms part of the output circuit.
The common emitters of transistors 20 and 22 to-gether provide an output terminal èlement for the first stage (the output terminal being identifiad on the drawing as circuit point 24). This output terminal in turn is con-nected to a further part of the output circuit generally indicated at 26. The output load comprises all the cir-cuitry connected to terminal point 24, including the output circuitry 26 and a multi-collector transistor 28 to be described hereinbelow.
The output circuitry 26 comprises a pair of Darlington-connected transistors 30,;32 which dri~e an external load 34. The load resistor 34 is paralleled by a resistor string 36 from which is derived a negative feed-back signal for the base of the second transistor 14 of the differential input pair.
The voltage-gain transistor 22 includes dual collectors which are connected toge~ther and to the emitter of another PNP transistor 38~acting~as a cascode. This cascode trànsistor 38;raises the output impedance of the amplifier, an important feature when the dynamic impedance of thè load is relatively high.
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The collector current of the cascode transistor 38 drives one transistor 40 of a current mirror generally indicated at 42. The other mirror transistor 44 supplies the bias tail current for the differential input transis-tors 12, 14. This mirror 42 thus reflects the current of the voltage-gain transistor 22 through the cascoded tran-sistor 38 to the emitters of the differential input tran-sistors 12, 14.
The emitter current for the ~ransistors 12, 14 will also flow in the load, that is,in the circuitry con-nected to circuit point 24. ~he load current comprises the current of the three paralleled collectors of transistor 28 and the very small amount of base current for the first Darlington transistor 30.
The current through the current mirror transistor 20 will be essentially equal to that of the~voltage-gain transistor 22. This is so because the currents in mirror transistors 44 and 40 will~necessarily be equall and there-fore the corresponding currents flowing in transistors 20 and 22 also must be equal. Thus the total signal current in the load at current point 24 will be essentially twice the current in the voltage-gain transistor 22. In effect, the transconductance of transistor 22 is doubled by this re-use of its current. This raises the overall gain by about ~ dB.
Yet a still more important result i5 however achieved by this biasing circuitry for the differential input stage transistors 12, 14. In more detail now, as noted above, the current mirror:42 forces the load current at circuit point 24 to split equally between the two common-emitter transistors ~0, 22. Moreovex, the base currents of transistors 20 and 22 also~will~be~equal, and will add re-spectively to the~equal currents of:the split collectors : ~ :: ; :
., .
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of transistor 20. (The cascode action of transistor 38 insures that the collector voltage of the voltage-gain transistox 22 will be very nearly the same as its base voltage -- and the base voltage of transistor 20 -- so that the Early effect will not unbalance the base currents Accordingly, the currents in the collectors of transistors 12 and 14 will be maintained essentially equal.
Consequently, it will be seen that the differ-ential input stage comprising transistors 12 and 14 always will be forced to ~e in balance by the biasing circuitry described. Changes in load current change ~he base volt-ages and the base currents of bo~h transistors 20 and 22 in such a way that the input stage remains in balance.
This in effect makes the amplifier gain independent of changes in the load.
It may be noted that the load at circuit point 24 is driven by the emitters of transistors 20 and 22.
This load connection to the emitters makes it possible to get at the collector current of the voltage-gain transistor 22 to use it to hold constant the ratio of the currents in the input stage transistors 12 and 14. This result is achiaved by holding constant the ratio of the Ioad current to the tail current of the input differential stage. As a consequence the differential voltage at the input stage is always extremely small.
The apparent load independence for the amplifier gain only works well over the range of currents where the transistors involved can operate normally. The Darlington transistors 30, 32 assist in that regard, making it possi-ble to develop substantial current for the external load 34 without reflecting significantly on the functioning of the previous stages. The Darlingtons also provide base bias for the cascode transistor 38.
The operating current for the ampiifier comes from the multi-collector transistor 28. This transistor is biased by a conventional circuit generally indicated at S0 which in the particular embodiment caused transistor 28 to produce a total of about 4~A, and reduced the powex supply voltage sensitivity. The transistor current is split by the multiple collectors, with about 3~A flowing into the common-emitter transistors 20, 22 and about l~A
driving another transistor 52. This latter transistor provides a tiny curre~t from its base to start the loop which runs from the emitter of the cascode transistor 38, to the current mirror 42, through the rigbt~hand input transistor 14 to the base of the voltage-gain transistor 22 and finally back to the cascode transistor 38. The little current from the base of transistor 52 insures that this loop will start. Its magnitude is comparable to the base current of the cascode transistor 38 so that it re-duces the error which results from the loss of collector current from voltage-gain transistor 22 by way of the base of the cascode transistor~.
A current-limiting arrangement also is included as part of the amplifier. A resistor 54 is connected in series with the output Darling~on transistor 32, which carries most of the output current, thereby to develop a voltage coxresponding to that output current. This voltage drives the base of a control transistor 56 which can rob emitter current from the`multi-collector transistor 28.
In order to make a big change in~the~emitter current, the control transistor 56 has to deliver a fairly large current to a resistor 58 in series with that emitter. This has the use~ul effect o "sharpening" the current limit, because when the control transistor ~ sufficient current for that purpose~ it has~a high transconductance,; so that fur-ther changes in the voltage~across~resistor 54 translate :
: ~ .
13 L2~
directly to the emitter of transistor 28. Although the control transistor 56 has a high transconductance, transis-tor 28 has a low transconductance which goes even lower with the onset of current limiting. As the latter transis-tor current is reduced, the amplifier continues to operate more or less normally due to low sensîtivity to its load current, Ultimately, as the current from the collectors of transistor 28 is reduced to the base current required by transistor 30 to supply the load, the amplifier will be completely starved and the output voltage will fall with any furt~er loading.
Although a specific preferred embodiment of the invention has been described herein in detail, this has been for the purpose of illustrating the principles of the invention, and should not necessarily be construed as limitïng the invention since it is apparent that those skilled in the art can make many modified axrangements of the invention without departing from the true scope thereof.
For e~ample, the input matched differential pair could be replaced by a mismatched pair to force a proportional-to-absolute-temperature (PTAT) current for a band-gap circuit.
Alternatively, the regulated output could be used to light up a basic band-gap reference which could be boosted by the amplifier. Still other variations will be apparent to those of skill in the art.
*
Claims (13)
1. An integrated-circuit high-gain amplifier comprising:
a differential amplifier stage including a pair of transistors with common emitters;
an input circuit connected to the base of one of said pair of transistors to receive an input signal;
transistor means arranged as a differential-to-single-ended converter and driven by said differential amplifier:
said transistor means having an output element producing a single-ended output signal;
an output circuit connected to said output element;
signal means coupled to the base of the other of said pair of transistors; and bias means for said differential amplifier, said bias means including circuit means for maintaining the currents through said differential pair of transistors in consant ratio substantially without regard to changes in load at said output element.
a differential amplifier stage including a pair of transistors with common emitters;
an input circuit connected to the base of one of said pair of transistors to receive an input signal;
transistor means arranged as a differential-to-single-ended converter and driven by said differential amplifier:
said transistor means having an output element producing a single-ended output signal;
an output circuit connected to said output element;
signal means coupled to the base of the other of said pair of transistors; and bias means for said differential amplifier, said bias means including circuit means for maintaining the currents through said differential pair of transistors in consant ratio substantially without regard to changes in load at said output element.
2. An IC amplifier as in Claim 1, wherein said signal means comprises means coupled between said output circuit and said other base.
3. An IC amplifier as in Claim 1, wherein said tran-sistor means comprises a transistor having its emitter serving as said output element.
4. An IC as in Claim 3, wherein said output circuit comprises a voltage-gain-transistor coupled to said tran-sistor means, the emitter of said voltage-gain transistor being connected to said transistor means emitter and driving said load.
5. An IC amplifier as in Claim 4, wherein said tran-sistor means includes means providing a current mirror having a pair of collectors connected respectively to the collectors of said differential pair of transistors;
one of said transistor means collectors also being connected to the base of said voltage-gain transistor.
one of said transistor means collectors also being connected to the base of said voltage-gain transistor.
6. An IC amplifier as in Claim 1, wherein said bias circuit means comprises feedback means responsive to a current developed in said output circuit for maintaining said differential amplifier currents in constant ratio.
7. An IC amplifier as in Claim 6, wherein said tran-sistor means comprises a transistor having an emitter serving as said output element;
said output circuit including a voltage-gain transistor with its emitter connected to said transistor means emitter;
said bias feedback means being responsive to the current through said voltage-gain transistor.
said output circuit including a voltage-gain transistor with its emitter connected to said transistor means emitter;
said bias feedback means being responsive to the current through said voltage-gain transistor.
8. An IC amplifier as in Claim 7, wherein said bias feedback means comprises a current mirror having as its input the current through said voltage-gain transistor;
the output of said current mirror providing the tail current for the emitters of said differential pair.
the output of said current mirror providing the tail current for the emitters of said differential pair.
9. An IC amplifier as in Claim 8, wherein said cur-rent mirror input is the collector current of said voltage-gain transistor.
10. An IC amplifier as in Claim 1, including a load connected to said transistor means to carry the current passing through said transistor means to said differential amplifier:
a voltage-gain transistor coupled to said tran-sistor means;
means connecting an element of said voltage-gain transistor to said load so that the load carries the cur-rent passing through said voltage-gain transistor; and means for forcing the load current to be shared equally by said transistor means and said voltage-gain transistor.
a voltage-gain transistor coupled to said tran-sistor means;
means connecting an element of said voltage-gain transistor to said load so that the load carries the cur-rent passing through said voltage-gain transistor; and means for forcing the load current to be shared equally by said transistor means and said voltage-gain transistor.
11. An IC amplifier as in Claim 10, wherein said load is connected to an emitter of said transistor means and to the emitter of said voltage-gain transistor.
12. An IC amplifier as in Claim 10, wherein said forcing means comprises a current mirror responsive to the collector current of said voltage-gain transistor and operable to produce a matching tail current for said dif-ferential pair of transistors.
13. An integrated-circuit amplifier comprising:
a pair of transistors each having a base, said transistors further including collector and emitter electrodes;
means connecting one set of common electrodes of said transistors together;
means to supply voltage signals to the bases of said pair of transistors;
transistor means arranged as a differential-to-single-ended converter and driven by said pair of transistors;
an output circuit connected to said transistor means to develop an output signal; and feedback means receiving a feedback signal from said output circuit and coupled to said common electrodes of said pari of transistors, said feedback means including a current mirror arranged to force the current through said pair of transistors to track said feedback signal from said output circuit.
a pair of transistors each having a base, said transistors further including collector and emitter electrodes;
means connecting one set of common electrodes of said transistors together;
means to supply voltage signals to the bases of said pair of transistors;
transistor means arranged as a differential-to-single-ended converter and driven by said pair of transistors;
an output circuit connected to said transistor means to develop an output signal; and feedback means receiving a feedback signal from said output circuit and coupled to said common electrodes of said pari of transistors, said feedback means including a current mirror arranged to force the current through said pair of transistors to track said feedback signal from said output circuit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/178,121 US4857862A (en) | 1988-04-06 | 1988-04-06 | High-gain IC amplifier |
| US178,121 | 1988-04-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1312928C true CA1312928C (en) | 1993-01-19 |
Family
ID=22651294
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000594865A Expired - Lifetime CA1312928C (en) | 1988-04-06 | 1989-03-28 | High-gain ic amplifier |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4857862A (en) |
| EP (1) | EP0410988B1 (en) |
| JP (1) | JP2893465B2 (en) |
| CA (1) | CA1312928C (en) |
| DE (1) | DE68929371T2 (en) |
| WO (1) | WO1989010026A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5105145A (en) * | 1988-05-04 | 1992-04-14 | Robert Bosch Gmbh | Voltage control circuit |
| US5214795A (en) * | 1989-06-29 | 1993-05-25 | Seiko Corp. | Low voltage automatic frequency control switch for a radio receiver |
| US4959622A (en) * | 1989-08-31 | 1990-09-25 | Delco Electronics Corporation | Operational amplifier with precise bias current control |
| US5406222A (en) * | 1993-12-22 | 1995-04-11 | Analog Devices, Inc. | High gain transistor amplifier |
| US6549070B1 (en) * | 2000-08-21 | 2003-04-15 | Analog Devices, Inc. | High gain amplifier with current limited positive feedback |
| US6563384B1 (en) | 2000-08-21 | 2003-05-13 | Analog Devices, Inc. | High gain amplifier with rail to rail range and frequency compensation |
| US6304109B1 (en) | 2000-12-05 | 2001-10-16 | Analog Devices, Inc. | High gain CMOS amplifier |
| US7667916B1 (en) | 2004-04-26 | 2010-02-23 | Marvell International Ltd. | Signal conversion system and method |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4122402A (en) * | 1977-07-05 | 1978-10-24 | Motorola, Inc. | Buffer amplifier circuit suitable for manufacture in monolithic integrated circuit form |
| US4188588A (en) * | 1978-12-15 | 1980-02-12 | Rca Corporation | Circuitry with unbalanced long-tailed-pair connections of FET's |
| US4213098A (en) * | 1979-02-09 | 1980-07-15 | Bell Telephone Laboratories, Incorporated | Semiconductor differential amplifier having feedback bias control for stabilization |
| DE3012635A1 (en) * | 1980-04-01 | 1981-10-08 | Robert Bosch Gmbh, 7000 Stuttgart | BRUSH HOLDER FOR ELECTRICAL MACHINES, ESPECIALLY FOR GENERATORS OF MOTOR VEHICLES |
| JPS56144614A (en) * | 1980-04-11 | 1981-11-11 | Toko Inc | Differential amplifying circuit |
| ATE14173T1 (en) * | 1981-08-06 | 1985-07-15 | Precision Monolithics Inc | CIRCUIT ARRANGEMENT FOR A DIFFERENTIAL AMPLIFIER WITH PRECISE ACTIVE LOAD. |
| JPH0758866B2 (en) * | 1985-05-15 | 1995-06-21 | 株式会社日立製作所 | Control pulse amplifier for VTR |
| DE3535882A1 (en) * | 1985-10-08 | 1987-04-16 | Licentia Gmbh | CIRCUIT ARRANGEMENT FOR SIGNAL GAIN |
-
1988
- 1988-04-06 US US07/178,121 patent/US4857862A/en not_active Expired - Lifetime
-
1989
- 1989-03-21 JP JP1503908A patent/JP2893465B2/en not_active Expired - Lifetime
- 1989-03-21 DE DE68929371T patent/DE68929371T2/en not_active Expired - Lifetime
- 1989-03-21 WO PCT/US1989/001162 patent/WO1989010026A1/en active IP Right Grant
- 1989-03-21 EP EP89904354A patent/EP0410988B1/en not_active Expired - Lifetime
- 1989-03-28 CA CA000594865A patent/CA1312928C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0410988A1 (en) | 1991-02-06 |
| JPH03503702A (en) | 1991-08-15 |
| EP0410988A4 (en) | 1992-09-30 |
| EP0410988B1 (en) | 2002-02-13 |
| US4857862A (en) | 1989-08-15 |
| JP2893465B2 (en) | 1999-05-24 |
| WO1989010026A1 (en) | 1989-10-19 |
| DE68929371T2 (en) | 2002-07-11 |
| DE68929371D1 (en) | 2002-03-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |